1. Field of the Invention
The present invention relates to an audio reproducing apparatus for reproducing audio data that is to be reproduced in synchronism with video data, and to an audio reproduction control method for use in this apparatus.
2. Description of the Related Art
In these years, techniques for altering the reproduction speed of multimedia data such as video and audio have been developed.
Jpn. Pat. Appln. KOKAI Publication No. 9-261613 discloses a reproducing method that can alter a reproduction speed in an apparatus that receives and reproduces multimedia data. In this method, the reproduction speed is altered in accordance with the amount of residual data in a receiving buffer. Specifically, in this method, when the amount of residual data in the receiving buffer is large, the reproduction speed is increased. When the amount of residual data in the receiving buffer is small, the reproduction speed is decreased. Thereby, overflow or underflow of the receiving buffer is prevented.
Jpn. Pat. Appln. KOKAI Publication No. 5-135228 discloses a technique that realizes decelerated reproduction or accelerated reproduction of voice signals while maintaining high-quality reproduction, by increasing or decreasing voiceless time periods in the voice signals.
Recently, there is a demand for the advent of techniques for reproducing video data and audio data, which are to be reproduced in synchronism, using different apparatuses.
However, when video data and audio data are to be reproduced by separate apparatuses, the reproduction timing of the video data is controlled according to the time indicated by the clock provided in the apparatus for reproducing the video data. The reproduction timing of the audio data is controlled according to the time indicated by the clock provided in another apparatus for reproducing the audio data. The difference between the clock referred to for the video data reproduction timing and the clock referred to for the audio data reproduction timing causes asynchronism between reproduced video and audio. If the reproduction speed of video data or audio data is altered in order to eliminate the asynchronism, an unnatural impression may be given to the viewer/listener.